New sources of atmospheric observations, faster supercomputers and advances in science together revolutionized weather forecasting in the latter part of the 20th century. On the global scale, we can today...

The present Global Framework for Climate Services (GFCS) with a vision “to enable society to better manage the risks and opportunities arising from climate variability and change, through the development and incorporation of science-based climate information and prediction into planning, policy and practice” carries forward and builds on the solid foundation laid by the Climate Information and Prediction Services (CLIPS) project.

As atmospheric CO 2 continues to increase, more and more CO 2 enters the ocean, which reduces pH (pH is a measure of acidity, the lower the pH, the more acidic the liquid) in a process referred to as ocean acidification. Declines in surface ocean pH due to ocean acidification are already detectable and accelerating.

The Montreal Protocol on Substances that Deplete the Ozone Layer, signed in 1987, has been successful in that the amount of chlorofluorocarbons is now slowly diminishing. A common misunderstanding, however, is the belief that the ozone problem has been solved and the ozone layer is back to its original state.

Data repositories and archives play a critical role as the source for the observational data used in the study of weather and climate. After over two centuries of recording observations on paper, observations in the last 20 years have mostly been collected digitally. Creating homogeneous, complete data sets from disparate collections is a fundamental challenge facing the climate research community.

Weather prediction has achieved immense progress, driven by research and increasingly sophisticated telecommunication, information technology and observational infrastructure. Predictive skill now extends in some cases beyond 10 days, with an increasing capability to give early warning of severe weather events many days ahead.